Early lunch boosts weight loss

The number of calories consumed in the course of a day is important, but weight loss can happen faster for those who eat their biggest meal early in the day, a new study has found.

New research suggests that people who eat lunch as their main meal before 3.00 pm lose weight faster, and are less likely to show signs of insulin resistance, than people who like to eat late.

People who eat later in the day are also likely to lose less weight than the early eaters.

A team of researchers from Brigham and Women's Hospital (BWH) and Tufts University in Boston, and the University of Murcia in Spain carried out the first large-scale, prospective study to demonstrate the effects of timing on weight loss programmes.

Writing in the online edition of the International Journal of Obesity, study senior author Frank Scheer said the timing of meals was a predictive factor in the effectiveness of weight-loss programmes.

Boston-based Scheer, an associate neuroscientist who directs the Medical Chronobiology Program said that late eaters studied by the team lost 'significantly less weight' than early eaters.

Previous animal research has shown that the timing of food intake has an impact on weight regulation.

However, until now, there have been no studies to confirm a similar link in humans.

Scheer and colleagues studied data on 420 overweight people who took part in a 20-week weight loss programme in Murcia, Spain.

In this part of the Mediterranean, lunch is the main meal of the day, and typically takes up around 40% of a person's daily intake of calories.

The study participants were roughly balanced between men and women, and had an average age of 42.

Around 50% of them ate their lunch before 3.00 pm, while the rest ate it after 3.00 pm.

Those who ate an early lunch lost far more weight than the later lunchers, who lost it more slowly. They also had a lower estimated rate of insulin sensitivity, which is a possible indicator for diabetes.

Previous research has shown other factors can play a role in weight loss. They include the total number of calories consumed, energy burned through activity, levels of appetite hormones leptin and ghrelin, the presence of the clock gene which impedes weight loss, and the amount of sleep a person gets.

When these factors were taken into account, there was little difference between the two groups.

However, it made little difference when the participants ate other meals that were smaller than lunch.